Rotax 912 ULS Low Oil Pressure at High RPM

Hope it all works out okay. 

Sometimes hose when cold are a little more firm and a tad harder to bend, but get them hot with oil and they bend easier. You may be able to rotate the brass fitting to keep it from kinking. This kink is literally right at the end of the brass fitting nipple. I would a fitting rotation if possible first.

If you can't hen a spring here may solve the kinking issue. The spring won't move because of the tension inside the hose walls that are applied to the spring.

For some who have never seen a spring in a hose I see them all the time from owners and aircraft MFG's in oil hoses, 17mm coolant hoses, 25mm (1") coolant hoses and even in 3/8" fuel hoses that make sharp hard bends.

Umm Rolf, 

Just how old are those oil lines? Do the fuel lines look like the oil lines?

With the kink removed from the oil supply line from the tank, the next ground static test showed the oil pressure at 40 psi on the mechanical oil pressure gauge at 4000 to 5000 rpm so I think that was the problem with the low oil pressure at high rpms. 

However, I'm getting pressure fluctuations on the mechanical gauge from 2000 rpm to 4000 rpm anywhere from 40 to 60 psi although the cockpit electric VDO gauge shows no fluctuation but it shows a lower psi of 30 throughout the entire rpm range.

Could the mechanical gauge fluctuations be a function of engine vibration since the electric VDO gauge is showing no fluctuations?  I have replaced the old spring and ball in the oil pressure relief valve with a new spring and the mushroom top.  Any more thoughts or ideas on the fluctuation issue are appreciated.  Thanks.   

Even without kinks, old hoses between the oil tank and pump inlet are particularly prone to collapsing. "On condition" inspection won't prevent a collapsing hose problem. Even after removal, my bad hose looked perfectly fine inside and out. The 5 year interval may be a bit too often, but I can guarantee that the 15 years that had passed on my new-to-me used aircraft was too long.